The Leonids 1999

Fine Display in 1999!

The first reports from Europe about observations of this year's Leonid meteors were received at ESO, just before 5 hrs MET (4 hrs UT). They indicated moderately intensive activity, with the maximum at about the time predicted (2 hrs UT). The peak may accordingly have been at about 15-20 meteors/min, possibly even higher. Despite clouds in most places, the observers were delighted!

Later reports from sites with clearer views contained higher numbers, up to 50-60 meteors/min. This corresponds to a major shower.

The following brief report summarises the event. It was published on November 18 on IAU Circular 7311 by the IAU Central Bureau for Astronomical Telegrams (CBAT): A pronounced peak in Leonid meteor activity occurred for about an hour centered on about Nov. 18d02h05m UT, agreeing very closely with predictions by Asher (1999, MNRAS 307, 919) and McNaught and Asher (1999, WGN 27, 85), which in turn suggest that the observed activity represents debris ejected from comet 55P/Tempel-Tuttle three revolutions ago. G. M. Hurst, Basingstoke, England, forwards a report from J. Mason that observations by members of the British Astronomical Association located north of Sharm El Sheikh, Egypt, revealed as many as 50 Leonids/min for a few minutes around the peak. Numerous other visual reports from observers in Jordan, Israel, Spain, and Portugal give similar results, as do data from radar monitoring by P. Pridal and R. Stork (Ondrejov) and radio monitoring by K. Suzuki (Toyokawa, Japan) and C. Steyaert (Mol, Belgium).

More information has become available on IAU Circular 7313, issued on November 20: A rather broad second peak in this year's Leonid display appears to have occurred around Nov. 18.6-18.9 UT, in which visual counts of 100-300 meteors/hr were reported by observers in Hawaii (S. J. O'Meara), Japan (K. Mameda, Y. Kushida, R. Kushida, T. Kagawa; communicated via S. Nakano), and China (Rui Qi; communicated via J. Zhu).

Interesting details about Leonids at the Moon (observed as vediorecorded flashes) are reported by D. W. Durham on IAU Circular 7320, issued on November 26.

More information is available at the sites linked from further down this page. Note in particular the detailed technical report from the International Meteor Organisation (IMO).

Below are excerpts from some of the reports received at ESO soon after the event (note that they represent the opinions of the authors!). Together they provide a kaleidoscopic view of a great event, a deep and personal experience for most involved.

From 02.57 to 03.15 (MET - ed. note) we (team from the Public
Observatory Sonnenborgh in Utrecht) observed hundreds of Leonids in a
sky that was partly clouded! Sometimes in only a few seconds we saw
several meteors, some of them seems to appear simultaneously! Most
were between magnitude 2 and 0, only a few fainter meteors were
seen. The brightest meteors were magnitude -4. Some color was seen,
mostly green. We think in this short period about 20 meteors per
minute were vissible, the real number must have been much higher since
we missed a lot (especially the fainter ones) because of the partly
clouded sky.
It was a great show!! But alike the eclipse it was much too short!
Robert Wielinga

From a group of Italian students:

We prepared observations from Torino and from Bologna: in Torino we
had very good weather conditions, in Bologna not so good. We observed
from about 3h10m until about 4h30m; the maximum was at the beginning
of our observation, direction south and we observed about 5 meteors
each minute for the first half hour of observation, then the
phenomenon was decreasing. Cold but interesting night!
Cristina Palici di Suni and Angela Turricchia

From Felipe E. Mac-Auliffe (La Silla, Chile):

I was watching the Leonids from La Silla during all the
night. The meteor shower wasn't so impressive from here, despite the
great weather conditions. I counted 10 bright ones (Mv ~ 0) and a lot
of faint ones. The average rate was about 20 meteors per hour.
I took several pictures using my Canon camera mounted on one of the
equatorial mounts that are located in the "Sarcofago", together with
an 11-inch Celestron telescope. I'm going down the mountain today and,
the first thing that I am going to do is to stop by the photo lab and
develop the film to see what came out...

From Jay Pasachoff (Williams College, USA):

I observed from the shore of the Mediterranean at El Saler, south
of Valencia, Spain, with my wife, Naomi, and daughter Deborah. We saw
Leonids at the rate of 12 a minute, or 720 per hour, for much of the
time in the crucial half hour centered on about the predicted time of
2:08 UT (3:08 local time). Sometimes meteors would come one per
second. Few fireballs appeared, but sometimes meteors appeared
simultaneously in double, almost parallel streaks across Orion, as the
radiant in Leo continued to rise in the eastern sky over the sea.
We saw a magnificent shower, by far the best I have ever seen, but not
quite the meteor storm that was at the top of our hopes. It began
about an hour before the predicted maximum, and few meteors had been
visible earlier in the evening.

The Leonids over here were my first real meteor storm. They weren't
extremely bright (the maximum I saw was mag = -2, but a friend who
stayed up longer saw what was a probably a -7). The peak was reached
as expected at 2 am and our basic statistics indicates around 750 -
800 per hour.
There weren't bright fireworks, but a lot of faint ones, a *lot*.

From Anders Vaesterberg (EAAE, Stockholm, Sweden):

18 students from two of our astronomy classes at Saltsjoebadens
Samskola (2nd year, 17 years old) and I observed the Leonids from the
Stockholm Observatory (59N 18E). Most of the time the sky was entirely
covered by clouds and sometimes it was even raining, but between about
2:30 local time and 2:45 (Central European Time, which is UT + 1 hour)
most of the sky was clear, and we could see meteors at a rate
corresponding to about 200 per hour. About half of them were of
magnitude 0 or brighter, often with smoky trails. Around 3:00 we saw
about 5 meteors/minute but then most of the sky was cloudy. Now the
meteors showed more colours, mostly green. Taking the light pollution
and the clouds into account, the rates should be much higher.
This was a thrilling and beautiful experience for all of us. A few
meteors were really marvellous with long trails. We agreed that if we
had seen only one of these, it would still have been worth the effort to
stay up so long in the cloudy, chilly and sometimes rainy night. Our
tiredness vanished completely when the clouds started to spread and this
celestial display became visible to us.

From the "Parsec-Astrorama" Club (Nice, France):

Last night, about 40 person were waiting for this astronomical
phenomenon. It began at 1h30 (local time). At this moment few Leonids
were visible. At 3h we could easily estimate that 1 000 - 1 200
Leonids per hour were visible in the sky. Beautiful !!!!

I observed the Leonids with 15 students of an Astronomy class at
Instituto Inca Garcilaso in Montilla (South of Spain). We started at
23:30 UT and finished at 3:30 UT. This was an impressive storm. By far
the best I have seen in all these years as a stargazer. We counted more
than 40 meteorites per minute. There weren't many bright fallen stars
but many of them appeared in pairs. I was astonished by the incredible
green colour of some meteors trails.

From Raul Lima (Porto, Portugal):

The observations reported below were done in Sande, Marco de
Canaveses, Portugal (about 41.05 N, 8.1 W, 40+ km E from Porto) with
cloudless skies, an almost clear horizon at East (exception made for a
nice-when-there-are-no-leonids-meteor-showers tree... but without
leaves, thankfully...), clear at South and West, clear above 10
degrees at North and partially blocked at Northwest.
The magnitude limit after 1h30 UT was about 6.1 at 40 degrees from the
horizon (East and North), and a little below that value in the other
directions.
Starting our observation at about 0.0 UT, we saw very few meteors until
about 1.0 UT (but during the first half hour the moon was still above
the horizon); after 1:00 UT there was a notorious crescendo - about
600 meteors/hour between 1h35 and 1h45 UT - with a peak between 2:00
UT and 2:20 UT of above 750 meteors/hour. Many faint meteors and few
fireballs (one of them with fragmentation, in south Monoceros). Around
the peak several (3, 4, five and even 6, once) simultaneous, making it
difficult to count, sometimes.
After 2h30 UT there was an also notorious decrease, with a slight peak
between 3h00 and 3h05 (not counted; maybe 5-6/ minute), when a short but
very bright fireball was seen, around magnitude -7. That fireball started
another show until about 4h45, where some -3 and -4 fireballs (one orange
but generally white-green) were seen, near Leo, among some swift and long
magnitude 1 and 2 meteors. The rate had then decreased to about 2-3/minute.
The observation ended at 5h10 UT.
Until about 3H00 UT, the observations were made with Cristina Dordio, Luis
Paulo Carrasqueiro, Filipe Pires and Elsa.

3 members of our observatory made their observations from "Cyclops"
observatory in Oostkapelle, Holland. It was a most enjoyable night!
We started at 00.00hrs, but there were a lot of clouds. At around
01.00hrs we started counting meteors by video-tape. On tape we have
243 Leonids!
Between 01.00 - 01.15hrs 5 leonids
01.15 - 01.30hrs 5 leonids
01.30 - 01.45hrs 20 leonids
01.45 - 02.00hrs 48 leonids
02.00 - 02.15hrs 80 leonids
02.15 - 02.30hrs 67 leonids
02.30 - 02.45hrs 22 leonids
Note: The Leonids mentioned were counted only in that part of the sky
that was covered by our Video-camera!
At 02.01 we counted 6 leonids per/minute
At 02.02 we counted 8 leonids per/minute
At 02.03 we counted 12 leonids per/minute
At 02.04 we counted 4 leonids per minute
The maximum was exactly at 02.03hrs. At 02.45 we stopped counting
because of the clouds. The Area we observed by Video was in the east:
Gemini, Orion, Taurus, Auriga. We were lucky that during the maximum
there were almost no clouds in this part of the sky.
We were probably the only people in the Netherlands who registered by
Video.
Rijk-Jan Koppejan

From the Sirius Astronomical Society of Kermanshah (Iran):

There was a quite pleasant mild cold, clear sky last night and the
members of the Society observed the shower all night. The rate was
about 15 per hour at early hours (from 2:00 in local time to 5:00 am,
i.e. from 11:30 pm to 1:00 am UT). Thereafter, the number grows to
60-100/hr and from 5:25 to 5:45 am (1:55 to 2:15 am UT).
Suddenly the rate rose to 25-30 meteors /min (1500-1800/hr). They were
very fast and their magnitudes were from -4.5 to +2 with a white to
yellow color.
We had the best view of observing in Iran as our city is in the far
west of the country at longitude 47 deg 5 min east; latitude 34 deg 19
min north; altitude of 1200 m. above the sea level.
M.A.Khodayari (M.D.)

From Olivier Vallejo (Bordeaux, France):

November the 18 of 1999 will be engraved for ever on my memory,
punctuating a year rich in celestial emotion (solar eclipse).
We are on Wednesday, the 17, in Montelimar, south-east of France, the
sky becomes overcast, and the hope to see the Leonid meteor shower
becomes gradually blurred.
A friend of mine phones me, telling me that southward the sky was
better, without hesitation we have to go to best horizons. At 30 km,
south-east of Montelimar, the show was about to begin, under a
fantastic sky with no luminous pollution. On the road to the
observation place, like a good omen, we saw some fireball in the Big
Dipper.
At 0h30 UT we arrived and began to settle down on the floor
comfortably, without thinking of what we were going to see.
One of my friends, a specialist of shooting stars, took his tape
recorder to record the number of shooting stars, with the
constellation name and the magnitude of each one, like we have done a
few months ago with the Perseid meteor shower.
According to some astronomical reviews, they announced in France,
between 500 and 600 meteors per hour during the maximum peak, number
close to what we saw for the Perseid meteor shower last summer. But,
one hour before the theoric maximum, this number was smashed, we
counted about 2000 meteors in the first half hour.
Sometimes a fireball split the sky, giving rise to a collective shout
of joy, until the Lion really begun to roar, taking out its sharp
claws, lacerating all the constellations.
The show must begin!
It was 1h30 UT when the cosmic symphony begun, the crescendi were
exceptional and the vision was magical. No sound, just a little
freezing breath of air coming from the North, we lay down, and,
keeping our eyes wide opened, we savoured with a great emotion the
beautifull fireworks the sky gave us. The Earth had just crashed
headlong into the remnants of the comet Temple Tuttle.
About ten arrows covered my field of view per second, paralysing me,
like pinned to the ground by a mystery force. According to my
estimates, the ZHR was about 30000 during the maximum peak, from 2h15
UT to 2h50 UT. I had a special thought to those who did not see such
a show.
The apotheosis, the firework finishing, occured when a huge fireball
dazzled us during some seconds, leaving a trace in the sky 15 degrees
long, 30 minutes wide.

A NIGHT TO REMEMBER - WHAT A SHOWER!
From old times, people believed when they see a meteor they can make a
wish. But in the Morning of Nov. 18, we rand out of wishes!
Our site was about 200km south of Tehran, 60km away from any light, on
the roof of an ancient place called the Palace of Bahram, in the
middle of the desert.
Close to 1:50am UT on Nov.18, the ZHR reached the highest level of
2500. It seems that we missed the highest peak at 1:55 AM with ZHR of
3500 because of morning light.
We started sky watching the night before (Nov. 16/17). No great Leonid
was seen, but a few woo-making Geminid fireballs! On the night of
Nov. 17, nothing happened until 2.30 AM day after. The ZHR increased
very fast and the peak was sharp. The sky above us was not
crystal-clear but a bit hazy. Most of the meteors were white with
magnitude 1-4, altough there were also dazzling fireballs in Ursa
Major and Orion (magnitude -4 to -9). The best picture we have
recieved up to now got 20 and a green point in the radiant.
The amazing point of the shower was that every 5 to 10 minutes or so
we had a couple of great meteors all over the sky and then it cooled
down until another peak. It seems that this year's Leonid stream had
many narrow parallel bands. Another point was a peculiarity of the
radiant. It was not very well focused, very vast in a few degrees.
We can call this year's shower a Baby Storm, but still not comparable
to last year's background stream with those unforgettable fireballs
over the lovely lands of Iran.

Good Prospects for the Leonids 1999

It is expected that the Leonid meteor shower will produce good displays in November 1999 as well as in the next years. Various predictions have been published in the past, but meteor watchers awaiting the Leonid shower in November 1998 were taken by surprise when a spectacular display of bright meteors occurred 16 hours before the predicted time for the maximum of the shower, see the Leonids 1998 webpage at ESO. In the meantime, explanations for this discrepancy have been put forward by various researchers who, at the same time, now venture to provide improved predictions.

The following text is extracted from a recent Press Release by the UK Royal Astronomical Society (30 August 1999; 459-pn97-12-nam ) and contains very useful information about the coming Leonid event. Further details may be found via the weblinks available below.

"The latest analysis, covering Leonid meteor storms over the past two hundred years, shows that the peak times of the strongest storms and sharpest outbursts are predictable to within about five minutes. The technique involves mapping the fine `braided' structure of the dense dust trails within the Leonid meteoroid stream. Although comet Tempel-Tuttle, the 'parent' of the Leonid stream, passed close to the Earth in 1998, Drs. David Asher (Armagh Observatory) and Rob McNaught (Australian National University) predict strong meteor storms in both 2001 and 2002. 1999 and 2000 will be less spectacular, but good. In 1999, observers at European longitudes are favoured, and may see up to 20 meteors a minute (in ideal conditions under a clear, dark sky) at around 2 a.m. (UT) on the morning of November 18th."

"Meteors, popularly known as 'shooting stars', can be seen on any night, given a sufficiently clear, dark sky. They are produced by the impact on the Earth's atmosphere of small dust grains released from comets. Most meteors arrive in 'showers' at fixed times of the year, when the Earth passes close to the orbit of the parent comet. But occasionally - just a few times a century - a phenomenon known as a meteor storm occurs. During a storm, meteors appear at astonishing rates, sometimes several per second. The most famous example, the incredible Leonid display of 1833, is credited with starting the serious scientific study of meteors."

Links

Additional information may be found at these major Leonid sites on the web: